D. Grdenić

The crystal and molecular structure of tetrakis(cyanomercuri)methane hydrate

The crystal structure of tetrakis(cyanomercuri)methane hydrate, C(HgCN)4 · H2O, has been determined from diffractometer X-ray intensity data by means of Patterson and Fourier methods and refined by the least-squares technique based on 911 independent reflections to the index R of 0.058 and Rω of 0.065. Crystals are monoclinic holohedral, space group P21/n with Z 4 formula units in the unit cell of dimensions a 8.520(5), b 13.622(8), c 10.783(6) A, β 92.48(5)°, Dobs 4.99 g cm−3, Dcalc 4.97 g cm−3. The structure consists of discrete molecules of tetrakis(cyanomercuri)methane and molecules of water of crystallization. The bond angles at the methane carbon atom range from 105(2) to 114(3)° and the mean HgC(methane) bond length is 2.05(3) A, while the distance of all the four mercury atoms from the geometrical centre of the tetrahedron is 2.053(3) A. The CHgC bond angles range from 175(3) to 178(2)°. The mean value of the HgC(cyanide) bond length is 2.03 A. The one OH⋯N hydrogen bond per water molecule is 2.77 A long.

Trimercurated acetic acid. The crystal structures of [Hg(H2OHg)(NO3Hg)CCOO]NO3 and 2(NO3Hg)3CCOOH·HNO3

Abstract Two nitrates of trimercurated acetic acid, obtained from the solution of mercuretin in nitric acid, were identified as [Hg(H 2 OHg)(NO 3 Hg)CCOO]NO 3 ( A ) and 2(NO 3 Hg) 3 CCOOH·HNO 3 ( B ) by X-ray diffraction. The cation of A is an infinite chain composed of the -Hg(H 2 OHg)(NO 3 Hg)CCOO- units joined through the CHgO linkages with mean bond lengths of 2.08(3) (CHg) and 2.11(3) A (HgO). The chains are connected by hydrogen bonding between the water molecule and the carboxyl oxygen with OH⋯O distances of 2.61(4) A. The structure of B consists of discrete molecules of (NO 3 Hg) 3 CCOOH. One half of the molecules in the unit cell join up to give centrosymmetrical pairs through the carboxyl groups, with OH⋯O bonds of 2.61(7) A, and the other half are hydrogen-bonded to the nitric acid via the carboxyl group, with an O⋯O distance of 2.59(8) A.

Trimercurated acetaldehyde. The crystal structure of [OHg3CCHO]NO3·H2O

Abstract The product of mercuration of acetaldehyde in aqueous mercuric-nitrate is a hydrated oxonium nitrate of tris(mercuri) acetaldehyde, [OHg3CCHO]NO3·H2O, the crystal structure of which has been determined. The crystals are tetragonal, space group P42/m with four formula units in the unit cell of dimensions a 10.755(3) and c 6.763(2) A. The structure was determined by means of X-ray diffractometry and refined by full-matrix least-squares method to an R value of 0.038. Mercuration of acetylene gives the same product but in polycrystalline form as shown by X-ray powder diagrams. The Hg3CCHO units are interconnected by oxonium oxygen atoms to a polymeric columnar [OHg3CCHO]nn+ cation. The nitrate ions show positional disorder. The geometry of the column is defined by a flat Hg3O oxonium pyramid and a slightly distorted Hg3CC tetrahedron, with HgO and HgC bond distances of 2.04(1) to 2.08(1) A.

Mercuretin as the condensation polymer of tris(acetoxymercuri)acetic acid. The crystal structure of (ClHg)3CCOOH · DMSO

Abstract It has been confirmed that the compound obtained by melting mercuric acetate (Stromeyer, 1809; Dimroth, 1902), named mercuretin (Marsh and Fleming Struthers, 1927), is identical with the compound prepared by heating mercuric acetate in acetic anhydride (Sand and Singer, 1903). Mercuretin, prepared by both routes, has been identified as the condensation polymer of tris(acetoxymercuri)acetic acid, AcO[HgC(HgOAc)2COO]nH, with n ∼ 10. Its hydrolysis in dilute hydrochloric acid gives tris(chloromercuri)acetic acid as the only mercury-containing product. The crystal structure of tris(chloromercuri)acetic acid dimethylsulfoxide solvate, (ClHg)3CCOOH · DMSO, has been determined by X-ray diffraction methods and refined by full-matrix least-squares to the conventional RW index of 0.074. The HgC bond length was fixed at 2.06 A in the final refinement, which gave a mean value of 2.33(3) A for the HgCl bond length.

Trimercurated acetaldehyde as the mercuration product of ethanol. The crystal structure of (ClHg)3CCHO·DMF and (BrHg)3CCHO·DMSO

Abstract The product obtained by boiling an ethanolic solution of mercuric chloride with sodium acetate (Hofmann, 1899) has been identified as tris(chloromercuri)acetaldehyde. The analogous bromomercuri derivative is obtained by using mercuric bromide. Both compounds crystallize from DMSO of DMF solution as the one-to-one solvates. The crystal structure of (ClHg)3CCHO·DMF (A) and (BrHg)3CCHO·DMSO (B) has been determined by X-ray diffraction methods and refined by full-matrix least-squares to the conventional R indices of 0.087 and 0.079, respectively. The mean value of the HgC bond length is 2.09(9) A in A and 2.04(7) A in B.

Trimercurated acetaldehyde. The crystal structures of 2[OHg3CCHO]NO3 · HNO3 and [HOHg2(NO3Hg)CCHO]NO3

Abstract Three new compounds 2[OHg3CCHO]NO3 · HNO3 (A), [HOHg2(NO3Hg)CCHO]NO3 (B) and (NO3Hg)3CCHO (C), have been successively obtained by mercuration of acetaldehyde with mercuric nitrate containing increasing concentrations of nitric acid. All of them contain trimercurated acetaldehyde. The orthorhombic crystals of A built up of parallel infinite networks of the polymeric trimercurated oxonium [OHg3CCHO]nn+ cation, while the monoclinic crystals of B contain polymeric dimercurated oxonium [HoHg2(NO3Hg)CCHO]nn+1 cation in the form of an infinite helical chain. The structures were determined by X-ray diffraction and refined by full-matrix least-squares to the R value of 0.050 for A and 0.063 for B. The Hg-C and Hg-O distances are in the ranges 2.04 to 2.11 A and 2.11 to 2.18 A, respectively. The crystals of C were not suitable for X-ray structure analysis.

Tetrakis(trifluoroacetoxymercuri)methane and tetrakis(acetoxymercuri)methane as the reaction products of Hofmann's base with the corresponding acid: X-ray crystallographic evidence

It has been shown by X-ray structure analysis that the crystals obtained from the solution of ethane hexamercarbide (Hofmanns base) in trifluoroacetic or acetic acid are tetrakis(trifluoroacetoxymercuri)methane, C(HgOCOCF3)4, and tetrakis(acetoxymercuri)methane, C(HgOCOCH3)4, respectively.

Synthesis and crystal structures of tetrakis(nitratomercurio) methane monohydrate and bis(sulphatomercurio)bis(aquamercurio) methane

Abstract The products of the reaction of Hofmanns base, [CHg4O(OH)2OH2]n, with conc, nitric and sulphuric acid are tetrakis(nitratomercurio)methane monohydrate, C(HgNO3)4·H2O and bis(sulphatomercurio)bis(aquamercurio)methane, C(HgSO4)2(HgOH2)2. The structures were characterized by IR spectra and single crystal X-ray diffraction. In both structures the carbon atom is tetrahedrally surrounded by four mercury atoms.

Mercuration of n-butyric, n-valeric and isovaleric acid. The crystal structure of C2H5C(HgCl)2COOH · DMSO

Abstract n-Butyric acid has been shown to react with mercuric n-butyrate in n-butyric anhydride to give the condensation oligomer 2,2-bis(n-butyryloxymercurio)-n-butyric acid, C3H7COO[HgC(C2H5)(HgOCOC3H7)COO]nH, with n ≅ 4. Hydrolysis of this with dilute hydrochloric acid gives 2,2-bis(chloromercurio)-n-butyric acid which crystallizes from dimethylsulfoxide as the solvate C2H5C(HgCl)2COOH·DMSO, the crystal structure of which has been determined by X-ray diffraction. Each dimercurated acid molecule is linked through its carboxyl groups to a DMSO molecule by a short hydrogen bond of length 2.617(30) A. The HgCl bond lengths are 2.329(8) and 2.329(10) A respectively, and mean value of HgC bond length is 2.093(31) A. The corresponding 2,2-bis(chloromercurio)-acids have been obtained from the mercuration products of n-valeric and isovaleric acid.

Monomercurated acetic acid. The crystal structure of NO3HgCH2COOH

Abstract Mercuration of acetic acid with mercuric acetate gives a condensation polymer of monomercurated acetic acid, CH 3 COO[HgCH 2 COO] n H, with n ≅ 10, which is soluble in alkali. The hydroxymercurioacetic acid polymer, OH[HgCH 2 COO] n H·H 2 O, with n ≅ 10, separates when the alkaline solution is treated with carbon dioxide, and treatment of this with hydrochloric and nitric acid gives ClHgCH 2 COOH and NO 3 HgCH 2 COOH, respectively. An X-ray diffraction study of NO 3 HgCH 2 COOH shows it to consist of dimers in which the molecules are linked through their pairs over carboxyl groups by centrosymmetric hydrogen bonds 2.67(2) A long. The HgC and HgO bond distances are 2.08(2) and 2.10(2) A, respectively.